Preparation And Application Of Solid Polymer Electrolyte Based On Deep Eutectic Solvent

The current electrochemical gas sensor is usually a closed container composed of a gas permeable membrane,a counter electrode,a working electrode,a reference electrode and an electrolyte solution.Among the commonly used electrolyte solutions,ionic liquids such as imidazoles have problems such as complicated synthesis,difficulty in purification,high production cost,toxicity,and unfriendly environment.Therefore,it is necessary to find environmentally friendly and inexpensive ionic liquids to meet the future development of society.The paper aims to find a new type of ionic liquid,and prepare it into a solid electrolyte to replace the liquid electrolyte of the traditional electrochemical gas sensor,and apply it to the NO2 sensor.The main work and conclusions of this thesis are as follows:(1)A deep eutectic solvent(DES)was prepared by heating choline chloride/1,3 butanediol(CHCl/BG)in a constant temperature water bath.The DES heat treatment temperature is 80～100℃,the heat treatment time is 5～13min,and the microscopic morphology of DES is observed by TEM.The best formula is CHCl:BG=1:1.(2)After mixing with PVDF,DES and NMP,a porous electrolyte is prepared according to a certain preparation process,and then it was characterized and analyzed by Fourier transform infrared spectroscopy(FTIR)、cyclic voltammetry(CV)、X-ray photoelectron spectroscopy(XPS)、scanning electron microscopy(SEM)、differential scanning calorimetry(DSC)and X-ray diffraction(XRD).The best formulation for solid electrolyte preparation:PVDF:DES:NMP=1:1:4(mass ratio);the optimum heat treatment condition is 90℃,6min.(3)Using a screen printing process,a 4cm x 4cm square-finger three-electrode structure was printed on a PET film using ten conductive carbon paste inks in Japan.The NO2 sensor was prepared by coating a solid electrolyte on the electrode.Experiments showed that under the optimal formulation of the solid electrolyte,the best sensitivity was obtained when the sensor coating thickness was 1.25mm.The sensitivity is 2.64nA/ppm,and the response and recovery time is 30s and 70s.In this paper,the application of eutectic solvent to the nitrogen dioxide sensor can simplify the production process and reduce the production cost.Therefore,under the premise of ensuring the sensitivity,it also provides a new idea and method for the manufacture of gas sensor.